update readme and use symlink for py-feos

feos-org · prehner · Nov 8, 2025 · Oct 24, 2025 · Oct 31, 2025 · Oct 31, 2025
commit 7bcb18701076738a529512b75231349398a51114
diff --git a/README.md b/README.md
@@ -10,6 +10,7 @@ The `FeOs` package provides Rust implementations of different equation of state
 
 ```python
 import feos
+import si_units as si
 
 # PC-SAFT parameters for methanol (Gross and Sadowski 2002)
 record = feos.PureRecord(
@@ -18,10 +19,12 @@ record = feos.PureRecord(
     m=1.5255,
     sigma=3.23,
     epsilon_k=188.9,
-    kappa_ab=0.035176,
-    epsilon_k_ab=2899.5,
-    na=1,
-    nb=1,
+    association_sites=[{
+      "kappa_ab": 0.035176,
+      "epsilon_k_ab": 2899.5,
+      "na": 1,
+      "nb": 1,
+    }]
 )
 
 # Build an equation of state
@@ -34,10 +37,10 @@ critical_point = feos.State.critical_point(eos)
 # Compute properties
 p = critical_point.pressure()
 t = critical_point.temperature
-print(f"Critical point for methanol: T={t}, p={p}.")
+print(f"Critical point for methanol: T={t/si.KELVIN:.1f} K, p={p/si.BAR:.1f} bar.")
 ```
 ```terminal
-Critical point for methanol: T=531.5 K, p=10.7 MPa.
+Critical point for methanol: T=531.5 K, p=106.5 bar.
 ```
 
 ## Models
@@ -65,6 +68,13 @@ Other public repositories that implement models within the `FeOs` framework, but
 ## Parameters
 In addition to the source code for the Rust and Python packages, this repository contains JSON files with previously published [parameters](https://github.com/feos-org/feos/tree/main/parameters) for the different models including group contribution methods. The parameter files can be read directly from Rust or Python.
 
+> :warning: The format for parameter files changed between releases `0.8.0` and `0.9.0`. You find parameters for new versions in the [parameters](https://github.com/feos-org/feos/tree/main/parameters) directory and for versions up to `0.8.0` in the [parameters_old](https://github.com/feos-org/feos/tree/main/parameters_old) directory.<br><br>
+If you maintain your own parameter files, there are two adjustments you need to make when upgrading to `feos 0.9.0`:
+> - Flatten the contents of the `model_record` field directly into the pure or segment record.
+> - Move association parameters into a list called `association_sites`. The 
+>
+> The structure of the JSON files and the `PureRecord` and `SegmentRecord` classes in Python is identical.
+
 ## Properties and phase equilibria
 
 The crate makes use of [generalized (hyper-) dual numbers](https://github.com/itt-ustutt/num-dual) to generically calculate exact partial derivatives from Helmholtz energy equations of state. The derivatives are used to calculate

diff --git a/license-apache b/license-apache
@@ -1,4 +1,4 @@
-   Copyright (c) 2021-present feos-org and Contributors.  https://github.com/feos-org/feos
+   Copyright (c) 2021-2025 feos-org and Contributors.  https://github.com/feos-org/feos
 
                                  Apache License
                            Version 2.0, January 2004

diff --git a/license-mit b/license-mit
@@ -1,4 +1,4 @@
-Copyright (c) 2023 Gernot Bauer, Philipp Rehner
+Copyright (c) 2021-2025 feos-org and Contributors.  https://github.com/feos-org/feos
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 

diff --git a/py-feos/README.md b/py-feos/README.md
diff --git a/py-feos/README.md b/py-feos/README.md
@@ -0,0 +1 @@
+../README.md